Kinesiology Ch.2

proprioceptors

internal receptors located in skin, joints, muscles, and tendons that provide feedback relative to tension, length, and contraction state of muscle, position of body and limbs, and movements of joints

muscle shape (length)

longer muscles can shorten through greater range more effective in moving joints through larger ROM

what fibers produce greater ROM than similar sized muscles with pennate arrangement?

parallel

extrinsic

pertaining usually to muscles that arise or originate outside of (proximal to) body part upon which they act

intrinsic

pertaining usually to muscles within or belonging solely to body part upon which they act

muscle size (diameter)

plays role in muscle's ability to exert force increased diameter = increased force extension

what does the muscle tend to do as it contacts?

pull both ends towards the gaster

active insufficiency

reached when muscle becomes shortened to the point that it can not generate or maintain active tension (cannot shorten any farther)

passive insufficiency

reached when opposing muscle becomes stretched to point where it can no longer lengthen and allow movement

location nomenclature

rectus femoris

unipennate fibers

run obliquely from tendon on one side only

bipennate fibers

run obliquely on both sides from central tendon

innervation

segment of nervous system that provides stimulus to muscle fibers

shape and location nomenclature

serratus anterior

action

specific movement of joint resulting from concentric contraction of muscle that crosses joint

proprioception

subconscious mechanism where body is able to regulate posture and movement by responding to stimuli originating in proprioceptors of the joints, tendons, muscles, and inner ear

what's happening at the contralateral leg while kicking a ball? (muscle roles)

synergists in hip (flex/ext/ab/add/rot) and pelvic area help stabilize the pelvis on that side to provide a relatively stable base for the hip flexors on the involved side to contract against

types of pennate fibers

unipennate bipennate multipennate

example of neutralizers during supination

when only supination action of biceps brachii is desired, the triceps brachii contracts to neutralize the flexion action of biceps brachii

2 types of isotonic contraction

concentric (shortening) eccentric (lengthening)

kinesthesis

conscious awareness of position and movement of the body in space

stabilizers (fixators)

contract to fixate/stabilize area to enable another limb or body segment to exert force and move

neutralizers

contract to resist/counteract/neutralize another muscle to prevent undesirable movements

points of attachment nomenclature

coracobrachialis (origin: coracoid process of scapula) (insertion: middle 1/3 of medial humerus)

dermatome

defined area of skin supplied by a specific spinal nerve

shape nomenclature

deltoid rhomboid

action nomenclature

erector spinae supinator pronator teres extensor digiti minimi

action and attachment nomenclature

extensor digitorum longus extensor hallucis longus

fiber direction nomenclature

external obliques

parallel fibers

fibers arranged parallel to length of muscle

tendon

fibrous connective tissue (cordlike) that connects muscles to bones and other structures

types of parallel fibers

flat fusiform strap

depth nomenclature

flexor digitorum superficialis (superficial) flexor digitorum profundus (deep)

size nomenclature

gluteus maximus gluteus minimus

multipennate fibers

have several tendons with fibers running diagonally between them

concentric contraction

-muscle develops active tension as it shortens -results in joint angle changing in direction of applied muscle force -accelerate movement or causes movement against gravity or external forces -total muscle length decreases under tension F is greater than R

isotonic contaction (dynamic)

-muscle develops active tension to either cause or control joint movement -varying degrees of muscle tension result in joint angles changing

eccentric contraction

-muscle lengthens under active tension -decelerates movement and controls body part to allow movement with gravity or external forces -total muscle length increases under tension R is greater than F

proprioceptors in muscles

-muscle spindle -Golgi tendon organs

proprioceptors in joints and skin

-Meissner's corpuscles -Ruffini's corpuscles -Pacinian corpuscles

isometric contraction (static)

-active muscle tension is developed but joint angle stay constant -often used to prevent movement in body segment -total muscle length stays the same under tension R = F

example of active and passive insufficiency while rectus femurs contracts concentrically to both flex hip and extend knee

-can completely perform either action one at a time but actively insufficient to obtain full ROM at both joints simultaneously -hamstrings can not stretch enough to allow both maximal hip flexion and maximal knee extension due to passive insufficiency

motor neurons (efferent)

-carry impulses from CNS to outlying body regions -innervated muscle fiber receives stimulus --> muscle contracts --> movement occurs

insertion

-distal attachment or part that attaches farthest from midline or center of body -most moveable part

synergist

-guiding muscles -work together to assist in refined action of agonists

antagonist muscles

-located on opposite side of joint from agonist and has opposite concentric action -reciprocal inhibition (to work in cooperation with agonist)

strap parallel fibers

-more uniform in diameter -long parallel manner -allows power to be focused onto small and bony targets

neural control of movement

-muscle contraction results from stimulation by the nervous system -single nerve cell (neuron) consists of cell body and projections (axons and dendrites) to carry impulses

2 types of fiber arrangement

-parallel -pennate

origin

-proximal attachment of muscle or part that attaches closest to midline -least movable part or attachment of muscle

examples of using sensory input for motor response

-see ball coming, catch it -feel a bug land on your arm, swat it away -feel like we are getting off balance, adjust -bottom getting sore, reposition/walk around

fusiform parallel fibers

-spindle shaped -central belly tapers to tendons on each end -allows them to focus their power onto small and bony targets

flat parallel fibers

-thin and broad -originating from broad, fibrous, sheet-like aponeuroses -allows force to be spread over broad area

sensory neurons (afferent)

-transmit impulses from receptors in the skin, joints, muscles, and other peripheral aspects of body to CNS -neuron may terminate in spinal cord or brain

action and size nomenclature

adductor brevis/longus/magnus

what are the agonist and antagonist muscles during elbow flexion?

agonist: biceps antagonist: triceps

what are the agonist and antagonist muscles during knee flexion?

agonist: hamstrings antagonist: quadriceps

example of muscle roles in kicking a ball (agonist, antagonist, synergists)

agonist: hip flexors and knee extensors (concentric) antagonist: hip extensors and knee flexors (relax) synergists: muscles that guide/refine the movement

what happens to the antagonist when the agonist contracts?

antagonist relaxes to lengthen allowing motion

pennate fibers

arranged obliquely to their tendons (like a feather) which increases cross sectional muscle area then increases power

number of divisions nomenclature

biceps brachii triceps brachii

what fibers produce the strongest contraction?

bipennate and unipennate fibers

agonist muscles

cause joint motion through a specified plane of motion when contracting concentrically

gaster (belly or body)

central, contractile portion of muscle that generally increases in diameter as muscle contracts

myotome

muscle or group of muscles supplied by a specific spinal nerve

what are the stabilizers during bicep curls?

muscles of scapula and glenohumeral joint (stabilizes shoulder and humerus so biceps can effectively do curls)